Driver circuit and semiconductor device

Abstract

A PMOS output stage and an NMOS output stage of which output impedances are controlled in accordance with impedance codes, a gate control part which drives output transistors held by the PMOS output stage and the NMOS output stage, and a slew rate control part which generates bias voltages to control driving ability of the gate control part based on an input current are included, and manufacturing variability of an input current circuit generating an input current is corrected by using the impedance code by the slew rate control part.

What is claimed is: 
     
       1. A driver circuit, comprising:
 a first output part in which plural first conductive transistors are connected in parallel, and an output impedance is controlled in accordance with first control information; 
 a second output part in which plural second conductive transistors are connected in parallel, and an output impedance is controlled in accordance with second control information; 
 a gate control part which drives the plural first conductive transistors held by the first output part and the plural second conductive transistors held by the second output part; and 
 a current source circuit which generates a signal controlling driving ability of the gate control part, 
 wherein the current source circuit includes: 
 plural first conductive transistors corresponding to the plural first conductive transistors held by the first output part and ON/OFF controlled based on the first control information; 
 a first resistor in which drains of the plural first conductive transistors are commonly connected to one end thereof; and 
 a signal generation part which receives a current flowing at the plural first conductive transistors and the first resistor as an input current, and generates a signal controlling the driving ability of the gate control part based on the input current. 
 
     
     
       2. The driver circuit according to  claim 1 ,
 wherein the current source circuit further includes: 
 a correction information generation part which corrects the first control information based on the first control information and the second control information, 
 wherein the plural first conductive transistors held by the current source circuit are ON/OFF controlled based on the first control information corrected by the correction information generation part. 
 
     
     
       3. The driver circuit according to  claim 2 ,
 wherein the correction information generation part corrects to make a value indicated by the first control information small when a value indicated by the control information is smaller than a certain value, and corrects to make the value indicated by the first control information large when the value indicated by the control information is larger than the certain value. 
 
     
     
       4. The driver circuit according to  claim 1 ,
 wherein the first output part is connected to an output terminal of the driver circuit via a second resistor, and 
 a ratio between a resistance by the plural first conductive transistors held by the current source circuit and the first resistor when the plural first conductive transistors held by the current source circuit are ON/OFF controlled in accordance with the first control information is equal to a ratio between a resistance by the plural first conductive transistors held by the first output part and the second resistor when the plural first conductive transistors held by the first output part are ON/OFF controlled in accordance with the first control information. 
 
     
     
       5. The driver circuit according to  claim 1 ,
 wherein the gate control part includes: 
 a logical circuit which performs a logical operation between the first control information and the second control information, and an input signal to the driver circuit; and 
 an inverter of which driving ability is controlled by a signal generated by the current source circuit, and which reverses an output of the logical circuit and outputs to the first output part and the second output part. 
 
     
     
       6. The driver circuit according to  claim 1 ,
 wherein the current source circuit includes a constant-current source circuit, and 
 wherein it is switchable whether a current flowing at the plural first conductive transistors and the first resistor is received by the signal generation part as the input current, or a current generated by the constant-current source circuit is received by the signal generation part as the input current. 
 
     
     
       7. The driver circuit according to  claim 1 ,
 wherein the signal generation part generates a bias voltage controlling the driving ability of the gate control part in accordance with the input current and supplies the bias voltage to the gate control part. 
 
     
     
       8. A semiconductor device, comprising:
 a driver circuit; and 
 a logic part which outputs a first control information, a second control information, an input signal, and a setting signal of driving ability of the gate control part to the driver circuit, 
 wherein the driver circuit includes: 
 a first output part in which plural first conductive transistors are connected in parallel, and an output impedance is controlled in accordance with the first control information; 
 a second output part in which plural second conductive transistors are connected in parallel, and an output impedance is controlled in accordance with the second control information; 
 a gate control part which drives the plural first conductive transistors held by the first output part and the plural second conductive transistors held by the second output part; and 
 a current source circuit which generates a signal controlling driving ability of the gate control part, 
 wherein the current source circuit includes: 
 plural first conductive transistors corresponding to the plural first conductive transistors held by the first output part and ON/OFF controlled based on the first control information; 
 a first resistor in which drains of the plural first conductive transistors are commonly connected to one end thereof; and 
 a signal generation part which receives a current flowing at the plural first conductive transistors and the first resistor as an input current, and generates a signal controlling the driving ability of the gate control part based on the input current.